A new set of emerging films are being beneficially employed in the development of high density semiconductor chips such as for example high density DRAM. These materials provide for higher capacity devices by allowing a reduction in the size of the individual features on the memory device. Accordingly, enhanced selectivity and profile control are required.
In the past, ion mills, which are a slow physical process, have been used to establish desired profiles on semiconductor wafers. Such ion mills have disadvantages in that the profile formed on the semiconductor wafer is sensitive to the angle of the ion mill beam and thus, the ion mill beam has to be accurately positioned to obtain the required profile. When profiles are obtained, however, large veils or ribs sticking up from the edges of the desired profiles have been experienced. Accordingly, ion mills are not well suited to emerging films.
Plasma etch processes for use in emerging films are faster, however such processes can in some cases provide unacceptable feature profiles. Accordingly, there is a need to provide an etching process which quickly and accurately process the emerging films that are used in the latest semiconductor products.